1. Field of the Invention
This invention relates to printed circuit boards (PCBS) and other electronic components such as CPUs and test probes, such devices from appropriate slots or connectors in a larger circuit device, including motherboards, and especially into such larger circuit devices that are adapted for testing the circuit performance either of such electronic components or of the larger circuit device.
2. Background Information
A number of different methods and apparatus have been devised for purposes of installing printed circuit boards (PCBs) into appropriate slots contained within the mother board of a computer, including the device described in U.S. Pat. No. 5,751,559 issued May 12, 1998 to Jensen et al. wherein the connecting direction of the PCB is perpendicular to its insertion direction. Other devices address both insertion and removal of a PCB, including the circuit board insertion and extraction tool of Hillis et al. described in U.S. Pat. No. 5,238,423 and 5,317,481, respectively issued on Aug. 24, 1993 and May 31, 1994; the lever-acting circuit board injector/ejector system described in U.S. Pat. No. 4,996,631 issued Feb. 26, 1991 to Freehauf; a similar device described in U.S. Pat. No. 5,139,430 issued Aug. 18, 1992 to Lewis et al.; another lever-acting device described in U.S. Pat. No. 5,162,979 issued Nov. 10, 1992 to Anzelone et al., which was also filed as European Appl. No. 90311407.2 on Oct. 17, 1990 and published as Publication No. 0 425 192 B1; and yet another lever-acting device described in U.S. Pat. No. 4,223,934 issued Sep. 23, 1980 to Cauceglia et al. Another device addresses inserting and removing PCBs into and from a motherboard without risking shorting out to adjacent, powered PCBS, described in U.S. Pat. No. 5,754,406 issued May 19, 1998 to Hardt et al.
Other technology is used in the context of installing integrated circuit (IC) devices (e.g., dual-in-line packages or "DIPs," surface mounted devices or "SMDs" and the like) into "burn-in" boards in which the devices are to be operated prior to distribution and sale, as in the vacuum operated, automated loader/unloader described in U.S. Pat. No. 5,093,984 issued Mar. 10, 1992 to Lape. In this device, a PCB carrier holding a burn-in board is translationally moved along a first horizontal axis and a "pick-and-place" unit to which are fed the ICs to be installed is translationally moved along a second horizontal axis perpendicular to that first horizontal axis, the positions of the ICs and corresponding sockets in the burn-in board being adjusted under computer control to permit installation and removal of the ICs.
In U.S. Pat. No. 4,583,288 issued Apr. 22, 1986 to Young, an apparatus is described that employs gripper means to grasp individual DIPs or the like and insert them into a PCB under pneumatic control. Another patent that relates to the installation of ICs and similar circuit components into PCBs is found in the automatic insertion universal work holding system describe in U.S. Pat. No. 4,291,867 issued Sep. 29, 1981 to Williams et al., which was also filed as European Appl. No. 81103252.3 on Apr. 30, 1981 and published as Publication No. 0 064 084 A1. In the prior art described within this patent, an insertion head is mounted above a work board holder on an X-Y table, onto which are mounted an array of PCBs into which components are to be inserted, each of such PCBs being fixedly positioned above a "window" aperture in the work board holder so as to permit access thereto from the underside thereof, it being asserted that the types of PCBs that can so be treated will be limited by their need to be matched against corresponding window apertures. The Williams et al. device mounts individual PCBs within individually controlled U-frame members for the purpose of accommodating PCBs of arbitrary size, dimension and orientation, and then from above a particular set of such PCBs so mounted, appropriate component feeding tracts and insertion devices are used to insert particular IC components into those PCBs.
A fluid-actuated and pneumatically-operated device for testing PCBs is described in U.S. Pat. No. 5,252,916 issued Oct. 12, 1993 to Swart, which was also filed as PCT Appl. No. WO 93/15409 on Jan. 14, 1993. Intended to supplant previous "bed of nails" devices in which a PCB is pressed downward onto an array of custom-activated and spring-loaded test probes, the Swart device employs a pneumatically operated flexible diaphragm to place an array of solid test probes into contact with corresponding test points on the PCB.
From the foregoing, it can be seen that while the art of pneumatic control and other methods of automatic manufacture have been applied to the task of inserting IC components or the like into PCBs, the task of inserting PCBs or similarly CPUs into underlying motherboards or the like has not received as much attention. Whether for "burn-in" purposes as treated in the device of Lape noted above as to IC components or for general testing purposes, it is also necessary that PCBs be installed temporarily into a larger circuit board. The prior art in this more specific area is found dominantly in box-like structures containing a lower platen into which a parent board is disposed horizontally above a "bed of nails" array of test probes or the like so as to be provided with necessary voltage and signals from the underside thereof, and then a fixture containing an assemblage of pre-positioned PCBs extending transversely downwardly (the edge connectors thereof facing downward) therefrom is placed within an upper platen, insertion of the edge connectors of those PCBs into the appropriate connectors or slots within the parent board then being accomplished by downward movement of the upper platen. A disadvantage of this system, however, is that no individual control of particular PCBs or other components is provided, and the substantial insertion force required to insert all of such PCBs and other components at one time, e.g., in the range of 300 lbs. of pressure, can frequently damage or break either a PCB or an underlying connector in the event of any misalignment. Because of the close spacing between "card slots" such as PCI and ISA connectors within the typical computer, and in other similar contexts, it has been proven quite difficult to devise any kind of system that would permit individual handling of PCBs in such "close quarters." It is thus the principal purpose of the present invention to provide a method and apparatus for removably installing printed circuit boards having edge connectors into corresponding receiving connectors mounted in larger circuit boards, in a way that has optimum convenience and is least likely to cause damage or breakage to the PCBs or other circuit boards so being treated, the method and apparatus so provided then being applicable as well to the handling of CPUs or other such devices.